The invention relates in general to positioning mounts for optical assemblies or components, and in particular to positioning mounts that are adhesively fixated.
Optical assemblies or components like for instance laser resonance assemblies feature a number of components that need to be precisely aligned relative to each other.
A typical optical assembly consists mainly of a planar assembly platform on which a number of devices are positioned relative to each other. The devices are attached to pedestals that provide varying degrees of freedom in the positioning.
U.S. Pat. No. 4,466,102 describes a modular dye laser. The pedestals introduced in this patent are mainly stacked plates that can slide along the planar top surface of a modular assembly platform. No specific method is provided to fixate the pedestals in the defined test position.
U.S. Pat. No. 4,827,485 describes a diode pumped solid state laser that is placed on a pedestal including an adjustment mechanism of essentially two wobble plates that can be rotated against each other. The pedestal provides a limited vertical adjustment without any fixating feature.
To fixate optical assemblies or components in their designated position the pedestals are typically soldered onto the assembly platform. The soldering process places an unfavorable thermal load on the assembly. Soldering of the pedestals themselves is also hard to accomplish without distorting the adjusted shape. The adjusted shape is defined of a number of individual mounts positioned in a friction resistant manner relative to each other.
UV-curing adhesives have been utilized to circumvent the problems associated with the soldering technique. Pedestals or mounts are at least partially made of translucent material such that a curing UV-light can be directed onto the adhesive film between the individual mounts.
U.S. Pat. No. 5,170,409 describes a laser resonator assembly that utilizes a translucent assembly platform on which the individual components of the laser resonator assembly are positioned. The individual components are adhesively attached to blocks that are also translucent. The invention provides a simple method to position and fixate the individual components.
Unfortunately, the manually applied adhesive cannot be applied evenly, which results in level differences between the individual components. Another shortcoming is that the adhesive with its relatively low viscosity and non-existent stiffness makes it difficult to maintain the defined position during the curing process. A further shortcoming is that the adhesive changes slightly its volume during the curing process, which also causes displacement of the individual components respectively within the pedestal mount. A further shortcoming is that the area at which the adhesive is applied is sensitive to unbalanced gravitational forces, which causes the adhesive to redistribute itself and consequently the blocks holding the individual components tilt. Another shortcoming is that the adhesive has a relatively high resilience, which causes the blocks to creep back towards the position prior to the positioning adjustment.
Therefore, there exists a need for a simple and economically fabricated mount that provides a free and precise positioning, which is maintained through the curing process.
It is a primary object of the present invention to provide a mount that can be precisely adjusted and that maintains the adjustment position throughout a fixating process.
It is a further object of the present invention to provide an adhesive junction between a mount and a structural element that utilizes a UV-curing adhesive.
It is a further object of the present invention to provide geometric shapes for the adhesive junction that allow free three dimensional positioning and orienting.
The present invention introduces mounts and structural elements that are adhesively attached to each other at adhesive junctions. The adhesive junctions consist of a moveable fixating area and a base fixating area. The moveable fixating area is typically part of a structural element designed to be adjusted relative to a mount. The base fixating area is part of the mount.
Contact edges are placed as boundaries on one of the fixating areas and snuggly contact the opposing fixating area.
During an adjustment process, while the adhesive has not been cured, the structural element can be adjusted relative to the mount. The contact edges slide in a predetermined fashion along the smooth surface of the opposing fixating area. The contact edges are typically at the edges of faces that are designated as fixating areas.
An adhesive film cavity is formed by the fixating area that features the contact edges. Since the contact edges are in direct contact with the opposing fixating area, the adhesive film cavity remains constant in shape and volume during the sliding adjustment process. The adhesive film cavity provides a sufficient volume for the adhesive between the fixating areas.
The contact edges provide a stiff contacting and referencing of the structural element relative to the mount. As a result, the contact edges make the adhesive junction form stable and independent of any redistribution of the adhesive between the fixating areas during the sliding adjustment.
The base fixating area can be a single planar face, which allows precise sliding and adjusting of the structural element in any direction and orientation within the plane of the planar face.
The base fixating area can comprise two planar faces at an angle to each other. This allows free and precise sliding and positioning of the structural element in the direction of intersection line between the two planar faces.
The base fixating area can be a cylindrical face, which allows precise sliding and adjusting of the structural element in any orientation around the axis of revolution of the cylindrical face and in any position in direction of the axis of revolution.
The base fixating area can be a conical face, which allows precise sliding and adjusting of the structural element in any orientation around the axis of revolution of the cylindrical face.
The base fixating area can be a spherical face, which allows precise sliding and adjusting of the structural element in any orientation around the center point of the spherical face.
The five basic geometric functions of the adhesive junction are implemented in a number of basic modules that can be combined with each other to build tree like assembly mounts. These assembly mounts are able to position and fixate according to the needs of any optical assembly.
The preferred material used for mounts and/or structural elements is sapphire, which has sufficient optical properties to direct the UV-light onto the adhesive during the curing and to be utilized as a functional part of the optical assembly. Sapphire has a relatively good thermal conductivity compared to other translucent materials such that it is able to drain and dissipate thermal energy, which is imposed on a structural element during the operation of the optical assembly.